java的时间工具类，包括找各种时间，根据固定格式返回时间

import org.apache.commons.lang3.time.DateFormatUtils;

import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.List;

/**
 * @author: Charlie
 */
public class DateUtils {

    public static final String DAYTYPE = "yyyy-MM-dd";

    public static final String DAYTIMETYPE = "yyyy-MM-dd HH:mm";

    public static final String TIMETYPE = "yyyy-MM-dd HH:mm:ss";

    public static final String DATETYPE = "yyyy年MM月dd日";

    public static final String DateTypeYear = "yyyy";

    public static final String DateTypeMonth = "yyyyMM";

    public static final String Date4ExportType = "yyyyMMdd";

    public static final String DateDetail4ExportType = "yyyyMMddHHmmss";

    //配合上面的类型传入format参数，返回想要的时间格式
    public static String formatDate(Date date, String format) {
        if (null == date) {
            return null;
        }
        return DateFormatUtils.format(date, format);
    }

    //获取当天的开始时间
    public static Date getDayBegin() {
        Calendar cal = new GregorianCalendar();
        cal.set(Calendar.HOUR_OF_DAY, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND, 0);
        return cal.getTime();
    }

    //获取当天的结束时间
    public static Date getDayEnd() {
        Calendar cal = new GregorianCalendar();
        cal.set(Calendar.HOUR_OF_DAY, 23);
        cal.set(Calendar.MINUTE, 59);
        cal.set(Calendar.SECOND, 59);
        cal.set(Calendar.MILLISECOND, 999);
        return cal.getTime();
    }

    //获取昨天的开始时间
    public static Date getBeginDayOfYesterday() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayBegin());
        cal.add(Calendar.DAY_OF_MONTH, -1);
        return cal.getTime();
    }

    //获取昨天的结束时间
    public static Date getEndDayOfYesterDay() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayEnd());
        cal.add(Calendar.DAY_OF_MONTH, -1);
        return cal.getTime();
    }

    //获取明天的开始时间
    public static Date getBeginDayOfTomorrow() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayBegin());
        cal.add(Calendar.DAY_OF_MONTH, 1);
        return cal.getTime();
    }

    //获取明天的结束时间
    public static Date getEndDayOfTomorrow() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayEnd());
        cal.add(Calendar.DAY_OF_MONTH, 1);
        return cal.getTime();
    }

    //获取本周的开始时间
    public static Date getBeginDayOfWeek() {
        Date date = new Date();
        if (date == null) {
            return null;
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
        if (dayofweek == 1) {
            dayofweek += 7;
        }
        cal.add(Calendar.DATE, 2 - dayofweek);
        return getDayStartTime(cal.getTime());
    }

    //获取本周的结束时间
    public static Date getEndDayOfWeek(){
        Calendar cal = Calendar.getInstance();
        cal.setTime(getBeginDayOfWeek());
        cal.add(Calendar.DAY_OF_WEEK, 6);
        Date weekEndSta = cal.getTime();
        return getDayEndTime(weekEndSta);
    }

    //获取本月的开始时间
    public static Date getBeginDayOfMonth() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(getNowYear(), getNowMonth() - 1, 1);
        return getDayStartTime(calendar.getTime());
    }

    //获取本月的结束时间
    public static Date getEndDayOfMonth() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(getNowYear(), getNowMonth() - 1, 1);
        int day = calendar.getActualMaximum(5);
        calendar.set(getNowYear(), getNowMonth() - 1, day);
        return getDayEndTime(calendar.getTime());
    }

    //获取本年的开始时间
    public static Date getBeginDayOfYear() {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, getNowYear());
        cal.set(Calendar.MONTH, Calendar.JANUARY);
        cal.set(Calendar.DATE, 1);
        return getDayStartTime(cal.getTime());
    }

    //获取本年的结束时间
    public static Date getEndDayOfYear() {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, getNowYear());
        cal.set(Calendar.MONTH, Calendar.DECEMBER);
        cal.set(Calendar.DATE, 31);
        return getDayEndTime(cal.getTime());
    }

    //获取某个日期的开始时间
    public static Timestamp getDayStartTime(Date d) {
        Calendar calendar = Calendar.getInstance();
        if(null != d){
            calendar.setTime(d);
        }
        calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        return new Timestamp(calendar.getTimeInMillis());
    }

    //获取某个日期的结束时间
    public static Timestamp getDayEndTime(Date d) {
        Calendar calendar = Calendar.getInstance();
        if(null != d) {
            calendar.setTime(d);
        }
        calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH), 23, 59, 59);
        calendar.set(Calendar.MILLISECOND, 999);
        return new Timestamp(calendar.getTimeInMillis());
    }

    //获取今年是哪一年
    public static Integer getNowYear() {
        Date date = new Date();
        GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
        gc.setTime(date);
        return Integer.valueOf(gc.get(1));
    }

    //获取本月是哪一月
    public static int getNowMonth() {
        Date date = new Date();
        GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
        gc.setTime(date);
        return gc.get(2) + 1;
    }

    //两个日期相减得到的天数
    public static int getDiffDays(Date beginDate, Date endDate) {
        if (beginDate == null || endDate == null) {
            throw new IllegalArgumentException("getDiffDays param is null!");
        }
        long diff = (endDate.getTime() - beginDate.getTime())/ (1000 * 60 * 60 * 24);
        int days = new Long(diff).intValue();
        return days;
    }

    //两个日期相减得到的毫秒数
    public static long dateDiff(Date beginDate, Date endDate) {
        long date1ms = beginDate.getTime();
        long date2ms = endDate.getTime();
        return date2ms - date1ms;
    }

    //获取两个日期中的最大日期
    public static Date max(Date beginDate, Date endDate) {
        if (beginDate == null) {
            return endDate;
        }
        if (endDate == null) {
            return beginDate;
        }
        if (beginDate.after(endDate)) {
            return beginDate;
        }
        return endDate;
    }

    //获取两个日期中的最小日期
    public static Date min(Date beginDate, Date endDate) {
        if (beginDate == null) {
            return endDate;
        }
        if (endDate == null) {
            return beginDate;
        }
        if (beginDate.after(endDate)) {
            return endDate;
        }
        return beginDate;
    }

    //返回某月该季度的第一个月
    public static Date getFirstSeasonDate(Date date) {
        final int[] SEASON = { 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4 };
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int sean = SEASON[cal.get(Calendar.MONTH)];
        cal.set(Calendar.MONTH, sean * 3 - 3);
        return cal.getTime();
    }

    //返回某个日期下几天的日期
    public static Date getNextDay(Date date, int i) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);
        cal.set(Calendar.DATE, cal.get(Calendar.DATE) + i);
        return cal.getTime();
    }

    //返回某个日期前几天的日期
    public static Date getFrontDay(Date date, int i) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);
        cal.set(Calendar.DATE, cal.get(Calendar.DATE) - i);
        return cal.getTime();
    }

    //获取某年某月到某年某月按天的切片日期集合（间隔天数的日期集合）
    public static List getTimeList(int beginYear, int beginMonth, int endYear,int endMonth, int k) {
        List list = new ArrayList();
        if (beginYear == endYear) {
            for (int j = beginMonth; j <= endMonth; j++) {
                list.add(getTimeList(beginYear, j, k));
            }
        } else {
            for (int j = beginMonth; j < 12; j++) {
                list.add(getTimeList(beginYear, j, k));
            }
            for (int i = beginYear + 1; i < endYear; i++) {
                for (int j = 0; j < 12; j++) {
                    list.add(getTimeList(i, j, k));
                }
            }
            for (int j = 0; j <= endMonth; j++) {
                list.add(getTimeList(endYear, j, k));
            }
        }
        return list;
    }

    //获取某年某月按天切片日期集合（某个月间隔多少天的日期集合）
    public static List getTimeList(int beginYear, int beginMonth, int k) {
        List list = new ArrayList();
        Calendar begincal = new GregorianCalendar(beginYear, beginMonth, 1);
        int max = begincal.getActualMaximum(Calendar.DATE);
        for (int i = 1; i < max; i = i + k) {
            list.add(begincal.getTime());
            begincal.add(Calendar.DATE, k);
        }
        begincal = new GregorianCalendar(beginYear, beginMonth, max);
        list.add(begincal.getTime());
        return list;
    }

    //获取某年某月的第一天日期
    public static Date getStartMonthDate(int year, int month) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, 1);
        return calendar.getTime();
    }

    //获取某年某月的最后一天日期
    public static Date getEndMonthDate(int year, int month) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, 1);
        int day = calendar.getActualMaximum(5);
        calendar.set(year, month - 1, day);
        return calendar.getTime();
    }

}